Putter head

ABSTRACT

This invention provides a putter head comprising a head body and a face insert mounted on a face surface of the head body. A notched portion is provided in a rear surface of the face insert to extend upward from a lower end portion.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the putter head of a golf putter and, more particularly, to a putter head including a face insert mounted on the face surface of the head body.

2. Description of the Related Art

A golf putter is a club that is mainly used to hit a ball on a green and roll it toward a cup. Japanese Patent Laid-Open No. 2007-117635 describes a technique for mounting a face insert on the face surface of a putter head to soften an impact feel.

Japanese Patent Laid-Open No. 2001-62008 describes a putter head in which the lower portion of the face surface is integrated with a synthetic resin foam to easily impart top spin to a ball. However, a synthetic resin foam has characteristics with a strong temperature dependence, so the effect of top spin changes considerably depending on the air temperature.

SUMMARY OF THE INVENTION

It is an object of the present invention to improve spin on a ball.

According to an aspect of the present invention, there is provided a putter head comprising a head body and a face insert mounted on a face surface of the head body, wherein a notched portion is provided in a rear surface of the face insert to extend upward from a lower end portion.

According to another aspect of the present invention, there is provided a putter head comprising a head body and a face insert mounted on a face surface of the head body, wherein a notched portion is provided in a rear surface of the face insert to extend downward from an upper end portion.

According to still another aspect of the present invention, there is provided a putter head comprising a head body and a face insert mounted on a face surface of the head body, wherein the face insert comprises a plate portion disposed on the face surface, and a bracket portion which is continuous with an upper edge of the plate portion and extends backward along a top surface of the head body, the bracket portion is fixed on an upper surface portion of the head body, and a rear surface of the plate portion and the head body are spaced apart from each other.

Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an exploded perspective view of a putter head according to an embodiment;

FIG. 1B is a front view of the putter head shown in FIG. 1A;

FIG. 1C is a sectional view taken along a line C-C in FIG. 1B;

FIG. 2 is an enlarged sectional view taken along a line I-I in FIG. 1B;

FIG. 3 is a perspective view of a face insert when viewed from the rear side;

FIGS. 4 to 7 are sectional views of face inserts of putter heads each according to another embodiment;

FIG. 8 is a perspective view showing a face insert of the putter head shown in FIG. 7 when viewed from the rear side;

FIGS. 9 and 10 are sectional views of putter heads each according to still another embodiment;

FIG. 11A is an exploded perspective view of a putter head according to still another embodiment,

FIG. 11B is a front view of the putter head shown in FIG. 11A;

FIG. 11C is a sectional view taken along a line C-C in FIG. 11B;

FIG. 12 is an enlarged sectional view taken along a line II-II in FIG. 11B;

FIG. 13 is a perspective view of a face insert when viewed from the rear side;

FIGS. 14 to 16 are sectional views of face inserts of putter heads each according to still another embodiment;

FIG. 17 is a sectional view of a putter head according to still another embodiment;

FIG. 18 is a perspective view showing a face insert of the putter head shown in FIG. 17 when viewed from the rear side;

FIGS. 19 and 20 are sectional views of putter heads each according to still another embodiment;

FIG. 21 is a perspective view of a putter head according to still another embodiment;

FIG. 22 is a front view of the putter head shown in FIG. 21;

FIG. 23 is a sectional view taken along a line III-III in FIG. 22;

FIG. 24 is an exploded perspective view of the putter head shown in FIG. 21;

FIGS. 25 to 31 are sectional views of putter heads each according to still another embodiment;

FIG. 32 is an exploded perspective view of the putter head shown in FIG. 31; and

FIGS. 33 and 34 are sectional views of face inserts of putter heads each according to still another embodiment.

DESCRIPTION OF THE EMBODIMENTS First Embodiment

This embodiment provides a putter head which imparts back spin, that is smaller in amount than in a general putter, to a ball upon striking the ball, to eventually facilitate creation of top spin of the ball, and exhibits a degree of top spin, that has a small temperature dependence.

FIGS. 1 to 3 show a putter head 1 according to this embodiment. The putter head 1 is provided with a recessed portion 2H in the front surface (face surface) of a head body 2, and a face insert 3 is disposed in the recessed portion 2H. In this embodiment, the head body 2 is made of a metal such as an aluminum alloy, a titanium alloy, a copper alloy, or stainless steel. The face insert 3 is made of a synthetic resin such as polyester, nylon, or urethane, or a metal such as an aluminum alloy, a copper alloy, or stainless steel. The front surface of the face insert 3 is flush with that of the head body 2 around the recessed portion 2H. The recessed portion 2H and face insert 3 both have an elongated, almost rectangular shape, when viewed from the front side. The recessed portion 2H has a uniform depth as a whole. However, the recessed portion 2H may be partly provided with a deep portion, or conversely, a shallow portion.

A notched portion 3 a is provided in the rear surface of the face insert 3 to extend upward from the lower edge portion. The notched portion 3 a extends from the left end of the face insert 3 to its right end. The rear surface of an upper edge portion 3 b on the rear surface of the face insert 3 is a flat surface parallel to the front surface of the face insert 3.

In this embodiment, the rear surface of the notched portion 3 a is also a flat surface parallel to the front surface of the face insert 3.

A plurality of female screw holes 3 c (a total of two, left and right female screw holes 3 c in this embodiment) are provided in the upper edge portion 3 b of the face insert 3, as shown in FIG. 3. A bolt insertion hole 5 (FIG. 2) runs through the head body 2 in the front-to-back direction at a position that matches the female screw hole 3 c. A bolt 6 inserted in each bolt insertion hole 5 is screwed into the female screw hole 3 c, thereby fixing the face insert 3 on the head body 2.

The face insert 3 has a horizontal dimension and vertical dimension that is slightly smaller than the recessed portion 2H, so a small gap 4 is formed between upper, lower, left, and right side surfaces 3S of the face insert 3 and a peripheral surface 2S (FIG. 1A) of the recessed portion 2H. The width of the gap 4 is preferably 0.3 to 1.5 mm and more preferably about 0.4 to 1.0 mm. As for the size of the face insert 3, its vertical dimension is preferably 16 to 30 mm and more preferably about 18 to 25 mm, its horizontal dimension is preferably 50 to 150 mm and more preferably about 70 to 100 mm, the thickness of the upper edge portion 3 b is preferably 2 to 10 mm and more preferably about 3 to 8 mm, and the thickness of the face insert in the notched portion 3 a is smaller than that in the upper edge portion 3 b by preferably 0.6 to 0.2 mm and more preferably 0.8 to 1.4 mm. However, the size of the face insert 3 is not limited to these specific values.

The face insert 3 is disposed in the recessed portion 2H such that its surface opposite to the notched portion 3 a becomes the face front surface of the putter, and the upper edge portion 3 b abuts against the bottom wall surface of the recessed portion 2H. As described above, the bolt 6 is inserted in each bolt insertion hole 5 to screw it into the female screw hole 3 c, thereby fixing the face insert 3 on the head body 2. Thus, the putter head 1 is formed.

A putter is formed by connecting a shaft to a hosel portion 1 h of the thus formed putter head 1. Upon putting with this putter (striking a ball on a green with the face surface), the front surface side of the lower portion of the face insert 3 slightly recedes upon hitting the ball, thereby easily imparting top spin to the ball. Thus, the hit ball exhibits good rectilinear movement characteristics.

In face inserts 3A to 3C shown in FIGS. 4 to 6, respectively, the front surface of the notched portion 3 a has an inclination different from that of the front surface of the notched portion 3 a in the face insert 3 mentioned above. In the face insert 3A shown in FIG. 4, the front wall surface defining the notched portion 3 a is inclined more to the front toward its upper portion. In the face inserts 3B and 3C shown in FIGS. 5 and 6, respectively, the front wall surface defining the notched portion 3 a is inclined more to the rear toward its upper portion. Note that in the face inserts 3, 3A, and 3B, the upper edge portion 3 b of the rear surface of the face insert and the front wall surface defining the notched portion 3 a have a stepped boundary between them, but in the face insert 3C shown in FIG. 6, the front surface of the notched portion 3 a is formed to directly intersect with the upper edge portion 3 b. Although not shown, the front wall surface defining the notched portion may at least partly have a curved surface.

FIG. 7 is a sectional view of the same portion as in FIG. 2 in a putter head 1A according to another embodiment, and FIG. 8 is a perspective view of a face insert 3 of the putter head 1A when viewed from the rear side.

In this embodiment, the notched portion 3 a is filled with a viscoelastic material 7. Rubber, an elastomer, or a soft synthetic resin, for example, is used as the viscoelastic material 7.

The viscoelastic material 7 has the same size as the notched portion 3 a, and the rear surface of the viscoelastic material 7 is flush with the upper edge portion 3 b of the face insert 3, but the viscoelastic material 7 may be thinner than the face insert 3. Also, the viscoelastic material 7 may have a horizontal dimension and vertical dimension smaller than the face insert 3.

Like the putter head 1A, when the notched portion 3 a is filled with the viscoelastic material 7, an impact sound and an impact feel upon hitting a ball can be adjusted.

Although the front surface of the face insert is flat in the above-described embodiments, a plurality of parallel elongated grooves may be provided. The groove preferably has a width (vertical dimension) of about 0.3 to 1.6 mm and a depth of about 0.05 to 1.1 mm.

Although the gap 4 is formed around the face insert 3 in the above-described embodiments, a viscoelastic material 8 such as rubber, an elastomer, or a synthetic resin may be disposed in the gap 4, like a putter head 1B shown in FIG. 9. Also, like a putter head 10 shown in FIG. 10, the face insert 3 may be formed to tightly fit in the recessed portion 2H so as to generate no gap 4.

Like the putter heads 1, 1A, and 1B shown in FIGS. 1 to 9, when the gap 4 or the viscoelastic material 8 is provided between the side surfaces 3S of the face insert 3 and the peripheral surface 2S of the recessed portion 2H, this prevents generation of residual stress in the face insert, thus producing an effect of obtaining rebound characteristics of the face insert, which comply with the design: Other arrangements in FIGS. 8 to 10 are the same as in FIG. 2, and the same reference numerals denote the same parts.

The above-described embodiments merely give examples of the present invention, and the present invention may be practiced in a mode other than those shown in the accompanying drawings. For example, the face insert may be fixed on the head body by a fixing means such as swaging or bonding other than bolting.

Second Embodiment

This embodiment provides a putter head which imparts top spin, that is smaller in amount than in a general putter, to a ball upon striking the ball, to eventually facilitate creation of back spin of the ball.

FIGS. 11 to 13 show a putter head 11 according to this embodiment. The putter head 11 is provided with a recessed portion 12H in the front surface (face surface) of a head body 12, and a face insert 13 is disposed in the recessed portion 12H. In this embodiment, the head body 12 is made of a metal such as an aluminum alloy, a titanium alloy, a copper alloy, or stainless steel. The face insert 13 is made of a synthetic resin such as polyester, nylon, or urethane, or a metal such as an aluminum alloy, a copper alloy, or stainless steel. The front surface of the face insert 13 is flush with that of the head body 12 around the recessed portion 12H.

The recessed portion 12H and face insert 13 both have an elongated, almost rectangular shape, when viewed from the front side. The recessed portion 12H has a uniform depth as a whole. However, the recessed portion 12H may be partly provided with a deep portion, or conversely, a shallow portion.

A notched portion 13 a is provided in the rear surface of the face insert 13 to run downward from the upper edge portion. The notched portion 13 a extends from the left end of the face insert 13 to its right end. The rear surface of a lower edge portion 13 b on the rear surface of the face insert 13 is a flat surface parallel to the front surface of the face insert 13.

In this embodiment, the rear surface of the notched portion 13 a is also a flat surface parallel to the front surface of the face insert 13.

A plurality of female screw holes 13 c (a total of two, left and right female screw holes 13 c in this embodiment) are provided in the lower edge portion 13 b of the face insert 13, as shown in FIG. 13. A bolt insertion hole 15 (FIG. 12) runs through the head body 12 in the front-to-back direction at a position that matches the female screw hole 13 c. A bolt 16 inserted in each bolt insertion hole 15 is screwed into the female screw hole 13 c, thereby fixing the face insert 13 on the head body 12.

The face insert 13 has a horizontal dimension and vertical dimension slightly smaller than the recessed portion 12H, so a small gap 14 is formed between upper, lower, left, and right side surfaces 13S of the face insert 13 and a peripheral surface 12S (FIG. 1A) of the recessed portion 12H. The width of the gap 14 is preferably 0.3 to 1.5 mm and more preferably about 0.4 to 1.0 mm. As for the size of the face insert 13, its vertical dimension is preferably 16 to 30 mm and more preferably about 18 to 25 mm, its horizontal dimension is preferably 50 to 150 mm and more preferably about 70 to 100 mm, the thickness of the lower edge portion 13 b is preferably 2 to 10 mm and more preferably about 3 to 8 mm, and the thickness of the face insert in the notched portion 13 a is smaller than that in the lower edge portion 13 b by preferably 0.6 to 0.2 mm and more preferably 0.8 to 1.4 mm. However, the size of the face insert 13 is not limited to these specific values.

The face insert 13 is disposed in the recessed portion 12H such that its surface opposite to the notched portion 13 a becomes the face front surface of the putter, and the lower edge portion 13 b abuts against the bottom wall surface of the recessed portion 12H. As described above, the bolt 16 is inserted in each bolt insertion hole 15 to screw it into the female screw hole 13 c, thereby fixing the face insert 13 on the head body 12. Thus, the putter head 11 is formed.

A putter is formed by connecting a shaft to a hosel portion 11 h of the thus formed putter head 11. Upon putting with this putter (striking a ball on a green with the face surface), the front surface side of the upper portion of the face insert 13 slightly recedes upon hitting the ball. As a result, the amount of top spin on the ball reduces, thus easily imparting back spin to the ball. Therefore, in a slightly rough green or a green that has good rolling property, a distance feel can be easily adjusted by low rolling property. That is, in general, a ball hit with a putter moves by sliding on the green surface with no rotation or low-speed rotation immediately after separating from the face surface of the putter, and, after a while, rolls without sliding on the green by friction between the ball and the green surface (the peripheral velocity and moving velocity of the ball become equal to each other). When a force which acts on a ball in the top spin direction upon hitting it with a putter head reduces, or when a force acts on a ball in the back spin direction upon hitting it with the putter head, the distance of sliding movement with no rotation or low-speed rotation immediately after the hitting increases. If the green surface is rough, the influence that the green surface exerts on the ball reduces during sliding movement with no rotation or low-speed rotation immediately after the hitting. As a result, the total rolling distance until the ball stops becomes nearly equal to that in a general green. Also, in a green with good rolling property (more specifically, a green in which lawn grass is cut short or a green tightened by, for example, a roller), rolling of the ball immediately after hitting it is suppressed as top spin weakens or back spin is generated. Thus, the total rolling distance until the ball stops becomes nearly equal to that in a general green. From the foregoing description, the putter head according to the present invention allows the player to easily adjust a distance feel in a slightly rough green or a green with good rolling property, that is, allows the ball to roll only by a distance intended by the player.

In face inserts 13A to 13C shown in FIGS. 14 to 16, respectively, the front surface of the notched portion 13 a has an inclination different from that of the front surface of the notched portion 13 a in the face insert 13 mentioned above. In the face insert 13A shown in FIG. 14, the front wall surface defining the notched portion 13 a is inclined more to the front toward its lower portion. In the face inserts 13B and 13C shown in FIGS. 15 and 16, respectively, the front wall surface defining the notched portion 13 a is inclined more to the rear toward its lower portion. Note that in the face inserts 13, 13A, and 13B, the lower edge portion 13 b of the rear surface of the face insert and the front wall surface defining the notched portion 13 a have a stepped boundary between them, but in the face insert 13C shown in FIG. 16, the front surface of the notched portion 13 a is formed to directly intersect with the lower edge portion 13 b. Although not shown, the front wall surface defining the notched portion may at least partly have a curved surface.

FIG. 17 is a sectional view of the same portion as in FIG. 12 in a putter head 11A according to still another embodiment, and FIG. 18 is a perspective view of a face insert 13 of the putter head 11A when viewed from the rear side.

In this embodiment, the notched portion 13 a is filled with a viscoelastic material 17. Rubber, an elastomer, or a soft synthetic resin, for example, is used as the viscoelastic material 17.

The viscoelastic material 17 has the same size as the notched portion 13 a, and the rear surface of the viscoelastic material 17 is flush with the lower edge portion 13 b of the face insert 13, but the viscoelastic material 7 may be thinner than the face insert 13. Also, the viscoelastic material 17 may have a horizontal dimension and vertical dimension smaller than the face insert 13.

Like the putter head 11A, when the notched portion 13 a is filled with the viscoelastic material 17, an impact sound and an impact feel upon hitting a ball can be adjusted.

Although the front surface of the face insert is flat in the above-described embodiments, a plurality of parallel elongated grooves may be provided. The groove preferably has a width (vertical dimension) of about 0.3 to 1.6 mm and a depth of about 0.05 to 1.1 mm.

Although the gap 14 is formed around the face insert 13 in the above-described embodiments, a viscoelastic material 18 such as rubber, an elastomer, or a synthetic resin may be disposed in the gap 14, like a putter head 11B shown in FIG. 19. Also, like a putter head 11C shown in FIG. 20, the face insert 13 may be formed to tightly fit in the recessed portion 12H so as to generate no gap 14.

Like the putter heads 11, 11A, and 11B shown in FIGS. 11 to 19, when the gap 14 or the viscoelastic material 18 is provided between the side surfaces 13S of the face insert 13 and the peripheral surface 12S of the recessed portion 12H, this prevents generation of residual stress in the face insert, thus producing an effect of obtaining rebound characteristics of the face insert, which comply with the design. Other arrangements in FIGS. 17 to 20 are the same as in FIG. 12, and the same reference numerals denote the same parts.

The above-described embodiments merely give examples of the present invention, and the present invention may be practiced in a mode other than those shown in the accompanying drawings. For example, the face insert may be fixed on the head body by a fixing means such as swaging or bonding other than bolting.

Third Embodiment

This embodiment provides a putter head which imparts back spin, that is smaller in amount than in a general putter, to a ball upon striking the ball, to eventually facilitate creation of top spin of the ball, and exhibits a degree of top spin, that has a small temperature dependence.

FIGS. 21 to 24 show a putter head 21 according to this embodiment. The putter head 21 is provided with a recessed portion 22H in the front surface (face surface) of a head body 22, and is also provided with a groove 22G in its top surface portion. The groove 22G is provided with female screw holes 22 a into which bolts 26 (to be described later) are screwed. A face insert 23 is disposed to engage with the recessed portion 22H and groove 22G. In this embodiment, the head body 22 is made of a metal such as an aluminum alloy, a titanium alloy, a copper alloy, or stainless steel. The face insert 23 is made of a synthetic resin such as polyester, nylon, or urethane, or a metal such as an aluminum alloy, a copper alloy, or stainless steel. The front surface of the face insert 23 is flush with that of the head body 22 around the recessed portion 22H.

The face insert 23 includes a plate portion 23 a which constitutes most of the face surface of the putter head 21, and a bracket portion 23 b extending backward from the upper edge of the plate portion 23 a, and has an inverted L-shaped longitudinal section in the front-to-back direction. The bracket portion 23 b is provided with bolt insertion holes 23 c. In this embodiment, the upper end face of the plate portion 23 a is exposed to the top surface portion of the head body 22.

The rear surface of the plate portion 23 a and the bottom wall surface of the recessed portion 22H are spaced apart from each other, and a viscoelastic material 27 is disposed between them to come into contact with them. Rubber, an elastomer, or a soft synthetic resin, for example, is used as the viscoelastic material 27. The viscoelastic material 27 may be connected by bonding or adhesion to the rear surface of the plate portion 23 a. Although the side end face and lower end face of the viscoelastic material 27 are flush with those of the plate portion 23 a in a given plane, they may recede from the given plane.

The bolt 26 is inserted in each bolt insertion hole 23 c to screw it into the female screw hole 22 a, thereby fixing the face insert 23 on the head body 22. Thus, the putter head 1 is formed.

The recessed portion 22H and the plate portion 23 a of the face insert 23 both have an elongated, almost rectangular shape, when viewed from the front side.

The plate portion 23 a has a horizontal dimension and vertical dimension slightly smaller than the recessed portion 22H, so a small gap 24 is formed between the upper, lower, left, and right side surfaces of the plate portion 23 a and the peripheral surface of the recessed portion 22H. The width of the gap 24 is preferably 0.3 to 1.5 mm and more preferably about 0.4 to 1.0 mm. As for the size of the plate portion 23 a, its vertical dimension is preferably 16 to 30 mm and more preferably about 18 to 25 mm, its horizontal dimension is preferably 50 to 150 mm and more preferably about 70 to 100 mm, and its thickness is preferably about 0.8 to 3 mm. However, the size of the face insert 3 is not limited to these specific values.

A putter is formed by connecting a shaft to a hosel portion 21 h of the thus formed putter head 21. Upon putting with this putter (striking a ball on a green with the face surface), the front surface side of the lower portion of the plate portion 23 a of the face insert 23 slightly recedes upon hitting the ball, thereby facilitating production of top spin. Thus, the hit ball exhibits good rectilinear movement characteristics. The viscoelastic material 27 has little influence on deformation of the plate portion 23 a, so the degree of top spin has no temperature dependence.

Like the putter head 21, when the viscoelastic material 27 is disposed on the rear surface of the plate portion 23 a, an impact sound and an impact feel upon hitting a ball can be adjusted.

Although the bottom wall surface of the recessed portion 22H is a vertical flat surface in the above-described embodiment, a putter head which is provided with a deep recessed portion 22 h in the bottom wall surface of the recessed portion 22H, and a viscoelastic material 27′ including, on its rear surface, a projecting portion fitted in the deep recessed portion 22 h, may be used, like a putter head 21′ shown in FIG. 25.

Although the viscoelastic material 27 or 27′ is disposed on the rear surface of the plate portion 23 a in the above-described embodiment, the viscoelastic material 27 or 27′ may be omitted to form a space portion between the rear surface of the plate portion 23 a and the bottom wall surface of the recessed portion 22H, like a putter head 21A shown in FIG. 26.

Although the gap 24 is formed around the plate portion 23 a of the face insert 23 in the above-described embodiments, a viscoelastic material 28 such as rubber, an elastomer, or a synthetic resin may be disposed in the gap 24, like a putter head 21B shown in FIG. 27A. Also, like a putter head 21C shown in FIG. 28A, the plate portion 23 a of the face insert 23 may be formed to tightly fit in the recessed portion 22H so as to generate no gap 24. Like putter heads 21B′ and 21C′ shown in FIGS. 27B and 28B, respectively, a deep recessed portion 22 h may be provided in the recessed portion 22H, and a viscoelastic material 27′ may be disposed.

Like the putter heads shown in FIGS. 21 to 27, when the gap 24 or the viscoelastic material 28 is provided between the peripheral surface of the face insert 23 and that of the recessed portion 22H, this prevents generation of residual stress in the face insert, thus producing an effect of obtaining rebound characteristics of the face insert, which comply with the design.

Like a face insert 23D of a putter head 21D shown in FIG. 29A, the plate portion 23 a may extend to the bottom surface of the putter head 21D. In the putter head 21D, a viscoelastic material 27D extends to the bottom surface of the putter head 21D as well. Note that the viscoelastic material 27D need not reach the bottom surface of the putter head 21D. Also, the viscoelastic material 27D may be omitted.

Like a face insert 23 of a putter head 21E shown in FIG. 30A, a depending portion 23 d may be provided at the rear end of the bracket portion 23 b, overlapping the rear surface of a head body 22E, and fixed on the head body 22E using a bolt 26. Note that a bolt insertion hole 23 e which receives the bolt 26 runs through the depending portion 23 d in the front-to-back direction. Like putter heads 21D′ and 21E′ shown in FIGS. 29B and 30B, respectively, a deep recessed portion 22 h may be provided in the recessed portion 22H.

Although the upper end of the plate portion 23 a reaches the upper end face of the head body in either of the above-described embodiments, an upper edge front surface 22 f of a head body 22F may hang over the plate portion 23 a of a face insert 23F so that the plate portion 23 a is disposed below the upper edge front surface 22 f. Other arrangements in FIGS. 31 and 32 are the same as in FIGS. 21 and 24, respectively, and the same reference numerals denote the same parts.

Although the rear surface of the plate portion 23 a is almost vertical in either of the above-described embodiments, the rear surface of the plate portion 23 a may be inclined, like face inserts 23G and 23H shown in FIGS. 33 and 34, respectively. In the face insert 23G shown in FIG. 33, the rear surface of the plate portion 23 a is inclined more to the front toward its lower portion. In the face insert 23H shown in FIG. 34, the rear surface of the plate portion 23 a is inclined more to the rear toward its lower portion. Note that although not shown, the rear surface of the plate portion 23 a may at least partly have a curved surface.

Although the front surface of the face insert is flat in the above-described embodiments, a plurality of parallel elongated grooves may be provided. The groove preferably has a width (vertical dimension) of about 0.3 to 1.6 mm and a depth of about 0.05 to 1.1 mm.

The above-described embodiments merely give examples of the present invention, and the present invention may be practiced in a mode other than those shown in the accompanying drawings. For example, the bracket portion of the face insert may be fixed on the head body by a fixing means such as swaging or bonding other than bolting.

Also, a plurality of face inserts including plate portions with different thicknesses may be prepared as spares, and one of these spares may be selected and mounted on the head body. With this arrangement, a face insert can be selected in accordance with, for example, the player's preferences and conditions and the conditions of a green in a golf course, and mounted on the head body. This makes it possible to adjust an impact feel and the degree of top spin. Note that when the viscoelastic material is disposed behind the plate portion, a plurality of viscoelastic materials with different thicknesses are also prepared as spares. Then, a viscoelastic material with an appropriate thickness is selected from the spares, and mounted on the head body such that the sum of the thickness of the plate portion and that of the viscoelastic material equals the depth of the recessed portion 22H.

Fourth Embodiment

The above-described third embodiment has given another example of the fixing structure of the face insert in the above-described first embodiment. This fixing structure is also applicable to the fixing structure of the face insert in the above-described second embodiment. In this case, the face insert includes a plate portion disposed on the face surface, and a bracket portion which is continuous with the lower edge of the plate portion and extend backward along the bottom surface of the head body. In other words, this face insert is obtained by inverting the face insert in the above-described third embodiment. Then, the bracket portion is fixed on the bottom surface portion of the head body, and the rear surface of the plate portion and the head body are spaced apart from each other. Other arrangements described in the above-described third embodiment are also applicable as needed to the fixing structure of the face insert in the above-described second embodiment.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

This application claims the benefit of Japanese Patent Applications No. 2010-227748, filed Oct. 7, 2010, No. 2010-251887, filed Nov. 10, 2010, and No. 2010-282035, filed Dec. 17, 2010, which are hereby incorporated by reference herein in their entirety. 

1. A putter head comprising a head body and a face insert mounted on a face surface of the head body, wherein a notched portion is provided, in a rear surface of the face insert to extend upward from a lower end portion.
 2. The head according to claim 1, wherein the notched portion extends from a left end of the face insert to a right end thereof.
 3. The head according to claim 1, wherein an upper edge portion of the rear surface of the face insert abuts against a bottom wall surface of a recessed portion provided in the face surface, and is fixed on the head body by a screw member.
 4. The head according to claim 1, wherein the notched portion is filled with a viscoelastic material.
 5. A putter head comprising a head body and a face insert mounted on a face surface of the head body, wherein a notched portion is provided in a rear surface of the face insert to extend downward from an upper end portion.
 6. The head according to claim 5, wherein the notched portion extends from a left end of the face insert to a right end thereof.
 7. The head according to claim 5, wherein a lower edge portion of the rear surface of the face insert abuts against a bottom wall surface of a recessed portion provided in the face surface, and is fixed on the head body by a screw member.
 8. The head according to claim 5, wherein the notched portion is filled with a viscoelastic material.
 9. A putter head comprising a head body and a face insert mounted on a face surface of said head body, wherein the face insert comprises a plate portion disposed on the face surface, and a bracket portion which is continuous with an upper edge of said plate portion and extends backward along a top surface of the head body, said bracket portion is fixed on an upper surface portion of the head body, and a rear surface of said plate portion and the head body are spaced apart from each other.
 10. The head according to claim 9, wherein a viscoelastic material is disposed between the rear surface of said plate portion and the head body.
 11. The head according to claim 9, wherein said bracket portion comprises a bolt insertion hole which vertically runs therethrough, and a bolt is screwed into the head body via said bolt insertion hole, thereby fixing the face insert on the head body.
 12. The head according to claim 9, wherein said bracket portion comprises a depending portion which hangs over a rear surface of the head body, a bolt insertion hole runs through said depending portion in a front-to-back direction, and a bolt inserted in said bolt insertion hole is screwed into the head body, thereby fixing the face insert on the head body.
 13. The head according to claim 9, wherein a groove is provided in a top surface of the head body to engage with said bracket portion.
 14. The head according to claim 9, wherein the face insert includes a plurality of face inserts including plate portions with different thicknesses as spares, and one of the face inserts, which is selected from the spares, is detachably mounted on the head body.
 15. The head according to claim 10, wherein the viscoelastic material includes a plurality of viscoelastic materials with different thicknesses as spares, and the viscoelastic material with a thickness corresponding to a thickness of the face insert is selected from the spares, and disposed between the rear surface of said plate portion and the head body. 